Embolic Protection Device

ABSTRACT

An embolic protection device includes a shaft, a first magnet fixedly coupled to a distal portion of the shaft, a second magnet slidingly coupled to the shaft proximal to the first magnet, and a filter including a distal portion coupled to the first magnet and a proximal portion coupled to the second magnet. The first and second magnets are magnetically attracted to each other such that in a radially compressed configuration of the filter, the second magnet is spaced from the first magnet a first distance, and in a radially expanded configuration of the filter, the second magnet slides towards the first magnet such that the second magnet is spaced a second distance from the first magnet, wherein the second distance is smaller than the first distance.

FIELD OF THE INVENTION

The invention relates generally to intraluminal distal protectiondevices for capturing particulate in the vessels of a patient. Moreparticularly, the invention relates to filter devices for capturingemboli in a blood vessel during an interventional vascular procedure,the filter having magnets to tether filters together or to open andclose the filters.

BACKGROUND

Catheters have long been used for the treatment of diseases of thecardiovascular system, such as treatment or removal of stenosis. Forexample, in a percutaneous transluminal coronary angioplasty (PTCA)procedure, a catheter is used to transport a balloon into a patient'scardiovascular system, position the balloon at a desired treatmentlocation, inflate the balloon, and remove the balloon from the patient.Another example of a common catheter-based treatment is the placement ofan intravascular stent in the body on a permanent or semi-permanentbasis to support weakened or diseased vascular walls, or to avoidclosure, re-closure or rupture thereof. More recently, catheters havebeen used for replacement of heart valves, in particular, the aorticvalve in a procedure sometimes known as transcatheter aortic valveimplantation (“TAVI”) or transcatheter aortic valve replacement(“TAVR”).

These non-surgical interventional procedures often avoid the necessityof major surgical operations. However, one common problem associatedwith these procedures is the potential release of embolic debris intothe bloodstream that can occlude distal vasculature and causesignificant health problems to the patient.

Medical devices have been developed to attempt to deal with the problemcreated when debris or fragments enter the circulatory system duringvessel treatment. One technique includes the placement of a filter ortrap downstream from the treatment site to capture embolic debris beforeit reaches the smaller blood vessels downstream. The placement of afilter in the patient's vasculature during treatment of the vascularlesion can collect embolic debris in the bloodstream.

It is known to attach an expandable filter to a distal end of aguidewire or guidewire-like member that allows the filtering device tobe placed in the patient's vasculature. The guidewire allows thephysician to steer the filter to a location downstream from the area oftreatment. Once the guidewire is in proper position in the vasculature,the embolic filter can be deployed to capture embolic debris. Someembolic filtering devices utilize a restraining sheath to maintain theexpandable filter in its collapsed configuration. Once the proximal endof the restraining sheath is retracted by the physician, the expandablefilter will transform into its fully expanded configuration inapposition with the vessel wall. The restraining sheath can then beremoved from the guidewire allowing the guidewire to be used by thephysician to deliver interventional devices, such as a balloonangioplasty catheter or a stent delivery catheter, into the area oftreatment. After the interventional procedure is completed, a recoverysheath can be delivered over the guidewire using over-the-wiretechniques to collapse the expanded filter (with the trapped embolicdebris) for removal from the patient's vasculature. Both the deliverysheath and recovery sheath should be relatively flexible to track overthe guidewire and to avoid straightening the body vessel once in place.

Another distal protection device known in the art includes a filtermounted on a distal portion of a hollow guidewire or tube. A moveablecore wire is used to open and close the filter. The filter is coupled ata proximal end to the tube and at a distal end to the core wire. Pullingon the core wire while pushing on the tube draws the ends of the filtertoward each other, causing the filter framework between the ends toexpand outward into contact with the vessel wall. Filter mesh materialis mounted to the filter framework. To collapse the filter, theprocedure is reversed, i.e., pulling the tube proximally while pushingthe core wire distally to force the filter ends apart. A sheath cathetermay be used as a retrieval catheter at the end of the interventionalprocedure to reduce the profile of the “push-pull” filter, as due to theembolic particles collected, the filter may still be in a somewhatexpanded state. The retrieval catheter may be used to further collapsethe filter and/or smooth the profile thereof, so that the filterguidewire may pass through the treatment area without disturbing anystents or otherwise interfering with the treated vessel.

TAVR procedures present difficulties not encountered in otherprocedures. For example, three branch vessels extend from the aorticarch towards the upper body. In particular, the right common carotidartery, which branches from the brachiocephalic artery, and the leftcommon carotid artery deliver blood to the brain. Emboli entering thesearteries pose an increased risk of stroke by blocking the smaller bloodvessels in the brain. Further, many TAVR procedures provide accessthrough the femoral artery, up through abdominal aortic, the aorticarch, and then crossing the aortic valve. Filter devices to be deployedto protect the carotid in many cases need to be delivered through adifferent pathway so that the delivery device for the filter does notinterfere with the delivery device for the replacement valve. Thisrequires an additional access site, such as the brachial artery.

Accordingly, there is a need for improved embolic protection devices forTAVR procedures.

SUMMARY OF THE INVENTION

Embodiments hereof relate to an embolic protection device including afirst filter configured to be disposed in a first vessel and a secondfilter configured to be disposed in a second vessel. A first tetherextends from a proximal end of the first filter and a first magnet iscoupled to the first tether. A second tether extends from a proximal endof the second filter and a second magnet is coupled to the secondtether. The device is configured such that when the first filter isdisposed in the first vessel and the second filter is disposed in thesecond vessel, the first magnet and the second magnet are magneticallycoupled to each other to couple the first tether to the second tether.

Embodiments hereof also relate to an embolic protection device includinga shaft, a first magnet fixedly coupled to a distal portion of theshaft, a second magnet slidingly coupled to the shaft proximal to thefirst magnet, and a filter including a distal portion coupled to thefirst magnet and a proximal portion coupled to the second magnet. Thefirst and second magnets are magnetically attracted to each other suchthat in a radially compressed configuration of the filter, the secondmagnet is spaced from the first magnet a first distance, and in aradially expanded configuration of the filter, the second magnet slidestowards the first magnet such that the second magnet is spaced a seconddistance from the first magnet, wherein the second distance is smallerthan the first distance.

Embodiments hereof also relate to an embolic protection system includingan inner shaft and a filter coupled to the inner shaft. The filterincludes a first filter portion and a second filter portion. A firstmagnet is fixedly coupled to a distal portion of the inner shaft, and adistal end of the second filter is coupled to the first magnet. A secondmagnet is slidingly coupled to the inner shaft proximal to the firstmagnet, and a proximal end of the first filter is coupled to the secondmagnet. A distal end of the first filter is coupled to a proximal end ofthe second filter. A connector is slidingly coupled to the inner shaftproximal of the second magnet. A plurality of support arms include aproximal end coupled to the connector and a distal end coupled to thefilter. The magnets are either magnetically attracted to each other ormagnetically repulsed from each other to expand the filter from aradially compressed configuration to a radially expanded configuration.The first filter may be a coarse mesh filter and the second filter maybe a fine mesh filter.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic illustration of an embolic protection device withthe filter in a deployed or expanded configuration.

FIG. 1A is a cross-sectional view of a portion of the embolic protectiondevice of FIG. 1.

FIG. 2 is a schematic illustration of the embolic protection device ofFIG. 1 in the delivery or radially compressed configuration.

FIGS. 3-8 are schematic illustrations of a method of delivering anddeploying two embolic protection devices and coupling them togetherusing magnets, and then retrieving the embolic protection devices aftera procedure is completed.

FIGS. 7A-7C are schematic details of steps of the method illustrated inFIGS. 7-8

FIG. 9 is a schematic detailed view of a portion of the embolicprotection device of FIG. 1.

FIG. 10 is a schematic detailed view of a portion of the embolicprotection device of FIG. 1 with the addition of a snare.

FIG. 11 is a schematic illustration of a locking mechanism coupled to amagnet of an embolic protection device.

FIG. 12 is a schematic illustration of the locking mechanism of FIG. 11with the magnets of each embolic protection device secured within thelocking mechanism.

FIGS. 13 and 14 are schematic illustrations of an embodiment of embolicprotection devices with shorter tethers and coupling tether, and amethod of coupling the embolic protection devices together using thecoupling tether.

FIGS. 15-17 are schematic illustrations of embolic protection deviceswherein one of the embolic protection devices includes a short tetherand the other includes a long tether, and a method of deploying andretrieving the embolic protection devices.

FIG. 18 is a schematic illustration of embolic protection devices withspring-like tethers and C-shaped magnets, and a method of deploying suchembolic protection devices.

FIGS. 19 and 19A are schematic illustrations of an embolic protectiondevice for deployment in a main vessel and in combination with embolicprotection devices deployed in branch vessels.

FIGS. 20-22 are schematic illustrations of an embolic protection deviceand a retrieval catheter with corresponding magnets to magneticallycouple the embolic protection device to the retrieval catheter duringretrieval of the embolic protection device.

FIGS. 23-25 are schematic illustrations of an embolic protection deviceutilizing magnets for deployment and retrieval thereof, and a method fordeploying and retrieving the embolic protection device.

FIGS. 26-28 are schematic illustrations of an embolic protection deviceutilizing magnets for deployment thereof, and a method for deploying andretrieving the embolic protection device.

FIGS. 29-31 are schematic illustrations of an embolic protection deviceutilizing magnets for deployment thereof, and a method for deploying andretrieving the embolic protection device.

FIGS. 32-34 are schematic illustrations of an embolic protection deviceutilizing magnets for deployment thereof and a fluid for retrievalthereof, and a method for deploying and retrieving the embolicprotection device.

FIGS. 35-37 are schematic illustrations of an embolic protection deviceutilizing magnets for deployment thereof, and a method for deploying andretrieving the embolic protection device.

FIG. 38 is a schematic illustration of an embodiment of an embolicprotection device with an extendable and retractable tether.

FIGS. 39-41 are schematic illustrations of the locking mechanism ofFIGS. 11-12 with the magnets of the embolic protection devices in analternative configuration.

DETAILED DESCRIPTION

Specific embodiments of the present invention are now described withreference to the figures, wherein like reference numbers indicateidentical or functionally similar elements. Unless otherwise indicated,the terms “distal” and “proximal” are used in the following descriptionwith respect to a position or direction relative to the treatingclinician. “Distal” and “distally” are positions distant from or in adirection away from the clinician, and “proximal” and “proximally” arepositions near or in a direction toward the clinician. In addition, theterm “self-expanding” is used in the following description withreference to one or more stent structures of the prostheses hereof andis intended to convey that the structures are shaped or formed from amaterial that can be provided with a mechanical memory to return thestructure from a compressed or constricted delivery configuration to anexpanded deployed configuration. Non-exhaustive exemplary self-expandingmaterials include stainless steel, a pseudo-elastic metal such as anickel titanium alloy or nitinol, various polymers, or a so-called superalloy, which may have a base metal of nickel, cobalt, chromium, or othermetal. Mechanical memory may be imparted to a wire or stent structure bythermal treatment to achieve a spring temper in stainless steel, forexample, or to set a shape memory in a susceptible metal alloy, such asnitinol. Various polymers that can be made to have shape memorycharacteristics may also be suitable for use in embodiments hereof toinclude polymers such as polynorborene, trans-polyisoprene,styrene-butadiene, and polyurethane. As well poly L-D lactic copolymer,oligo caprylactone copolymer and poly cyclo-octine can be usedseparately or in conjunction with other shape memory polymers.

The following detailed description is merely exemplary in nature and isnot intended to limit the invention or the application and uses of theinvention. Although the description of the invention is in the embolicfilters for use in conjunction with aortic valve procedures, the devicesand methods described herein can also be used in conjunction with otherprocedures at other locations. For example, and not by way oflimitation, the devices and methods described herein could be used forpercutaneous mitral valve replacements, coronary artery stentingprocedures, and carotid artery stenting procedures. Furthermore, thereis no intention to be bound by any expressed or implied theory presentedin the preceding technical field, background, brief summary or thefollowing detailed description.

Embodiments hereof are directed to embolic protection devices. Inparticular, embodiments hereof are directed to embolic protectiondevices including magnets and methods for using such devices. FIG. 1shows an embodiment of an embolic protection device 100. Embolicprotection device 100 includes a filter assembly 102 located adjacentthe distal end 104 of a delivery member 106. Delivery member 106 can bea modified guidewire assembly, hereinafter referred to as either“delivery member” or “guidewire”. Filter assembly 102 is delivered,deployed and retrieved by a sheath 108 arranged to be slid over filterassembly 102. When embolic protection device 100 is in a constrainedposition, filter assembly 102 is collapsed within sheath 108 as shown inFIG. 2. When filter assembly 102 is deployed, sheath 108 is withdrawn,releasing filter assembly 102 as shown in FIG. 1.

Filter assembly 102 includes a filter 110 and connecting struts 112connecting a proximal end of filter 110 to guidewire 106. In particular,as shown in FIG. 1, connecting struts 112 may be the wires or strandsthat form filter 110 grouped to form the connecting struts 112 andopenings 114 between connecting struts 112. Alternatively, connectingstruts 112 may be separate from filter 110 and be connected thereto, asdescribed, for example, in U.S. Pat. No. 6,346,116 to Brooks et al., thecontents of which are incorporated in their entirety by referenceherein. Connecting struts 112 are secured to a tether 119 at a proximalconnection 116 and distal end of filter assembly 102 is secured toguidewire 106 at a distal connection 118, as shown in FIG. 1. Tether 119and guidewire 106 may be extensions of each other or may be separateelements. In an embodiment, connections 116, 118 are fixed inlongitudinal positions but are capable of rotational movementindependent of the guidewire core while maintaining the longitudinalposition.

In the embodiment of FIGS. 1-2, filter 110 is a braided self-expandingor shape memory material, such as Nitinol. Filter 110 is shape set toreturn to the configuration shown in FIG. 1 upon release from sheath108. However, other filters and filter materials may be used. Forexample, and not by way of limitation, filter assembly 102 may besimilar to Medtronic's Defender embolic protection filter, withmodifications described herein. Further, filter assembly 102 may besimilar to the filter assemblies described in U.S. Pat. No. 6,346,116 toBrooks et al., the content of which is incorporated by reference herein.Other filter assemblies known to those skilled in the art may also beutilized.

Embolic protection device 100 further includes a magnet 120 coupled to aproximal end of tether 119. Magnet 120 may be coupled to tether 119 bydevices and methods known to those skilled in the art, such as adhesivesand mechanical fasteners. Magnet 120 may be a magnetic material or amaterial capable of being magnetized. Coupled to a proximal portion ofmagnet 120 is a wire loop 122, which is coupled to a tether 124. Wireloop 122 and tether 124 may be any construction which allows magnet 120and filter assembly 102 to be disconnected from tether 124 afterdeployment at a desired location. In the embodiment shown in FIGS. 1-2(and shown in more detail in FIG. 9), a multi-lumen shaft 121 isdisposed within sheath 108. Sheath 108 moves freely in an axialdirection over multi-lumen shaft 121. FIG. 1A shows a cross-section ofmulti-lumen shaft 121, including lumens 123 a and 123 b. Tether 124extends the length of the inner shaft 121 from a proximal end thereofthrough lumen 123 a, extends out of a distal end of lumen 123 a, loopsthrough wire loop 122, and back proximally through lumen 123 b ofmulti-lumen shaft 121. Ends of tether 124 are anchored to a handle (notshown) during navigation and deployment of embolic protection device100.

FIGS. 3-8 show a method of delivering and deploying a pair of embolicprotection devices 100 in branch vessels of the aortic arch 14, inparticular, the brachiocephalic artery 20 (also known as the innominateartery) and the left common carotid artery 22. As shown in FIGS. 3-8,the aorta 10 includes the ascending aorta 12, the aortic arch 14, andthe descending aorta 16. Between the ascending aorta 12 and the leftventricle (not shown) of the heart (not shown) is the aortic valve 18.Branching from the aortic arch 14 are the brachiocephalic artery 20, theleft common carotid artery 22, and the left subclavian artery 24. Thebrachiocephalic artery 20 branches into the right subclavian artery (notshown) and the right common carotid artery (not shown). Duringprocedures to repair or replace the aortic valve 18, embolic debris maybe dislodged and be delivered downstream with blood flow as shown inFIG. 6. Embolic filters or distal protection devices are utilized toprevent the debris from reaching and blocking narrower vessels. Inparticular, the right common carotid artery (not shown), which branchesfrom the brachiocephalic artery 20, and the left common carotid artery22 are particularly sensitive to embolic debris because they lead to thevessels of the brain. Accordingly, FIGS. 3-8 show embolic protectiondevices 100 delivered and deployed in the brachiocephalic artery 20 andthe left common carotid artery 22. However, those of ordinary skill inthe art would recognize that the devices and methods described hereinmay be utilized in other locations.

As shown in FIG. 3, a first embolic protection device 100 is advancedfrom the descending aorta 16 into the aortic arch 14 and intobrachiocephalic artery 20. Embolic protection device 100 may be advancedby access through the femoral artery using, for example, the Seldingertechnique. Other methods known to those skilled in the art may also beutilized. A second embolic protection device 100′ is also advancedthrough the descending aorta 16 into the aortic arch 14, and into theleft common carotid artery 22, as shown in FIG. 4. The second embolicprotection device 100′ may also be advanced by access through thefemoral artery. However, the access for one of the embolic protectiondevices may be through the left femoral artery to the left common iliacartery and into the descending aorta 16, while access for the other ofthe embolic protection devices may be through the right femoral arteryto the right common iliac artery and into the descending aorta. Otheraccess sites and paths may be utilized, as known to those skilled in theart.

After embolic protection devices 100, 100′ have reached into thebrachiocephalic artery 20 and the left common carotid artery 22,respectively, sheaths 108, 108′ are retracted such that filters 110,110′ are expanded within the respective artery, as shown in FIG. 4. Theorder of deployment of the baskets is not critical. For example, and notby way of limitation, second embolic protection device 100′ may bedelivered first, and sheath 108′ may be retracted to deploy filter 110′.Then first embolic protection device 100 may be delivered and sheath 100may be retracted to deploy filter 110, or the order may be reversed.Also, one of the two embolic protection devices may be delivered, thenthe other may be delivered, and then the filters can be deployed.

With the filters 110, 110′ deployed within their respective arteries,and the magnets 120, 120′ exposed by retraction of sheaths 108, 108′,the embolic protections devices 100, 100′ are maneuvered such thatmagnets 120, 120′ are sufficiently close to each other magneticallycouple to the each other, as shown in FIG. 5. Once magnets 120, 120′ arecoupled to each other, wire loops 122, 122′ are disconnected fromtethers 124, 124′, respectively. Tethers 124, 124′ are disconnected fromwire loops 122, 122′ by unlocking the proximal ends of the respectivetether 124, and pulling on one of the ends until the entire tether 124is removed. Alternatively, tethers 124, 124′ may be a suture materialformed into a loop that is cut to release wire loops 122, 122′, or amechanical loop that in unhinged or mechanically opened to release wireloops 122, 122′, or any other releasable connection known to thoseskilled in the art. Sheaths 108, 108′ with tethers 124, 124′ may beretracted out of the body, leaving filter assembly 102/filter 110deployed within the brachiocephalic artery 20, and filter assembly102′/filter 110′ deployed within left common carotid artery 22, as shownin FIG. 6. Further, the filter assemblies 102, 102′ are coupled togethervia tethers 119, 119′ extending into the aortic arch 14 and beingcoupled together via magnets 120, 120′, as also shown in FIG. 6. Withthe filters deployed as shown in FIG. 6, procedures for the aorticvalve, such as TAVI or valvuloplasty, may access the aortic valve areathrough the aortic arch 14 with minimal interference from the embolicprotections devices. During the procedure, embolic debris 28 travellingalong the blood flow represented by arrows 26 will be captured byfilters 110, 110′.

After the procedure is completed and the procedure devices have beenremoved, the filters 110, 110′ may be removed. In order to remove thefilters, a retrieval catheter 200 is advanced adjacent the location ofthe magnets 120, 120′. Retrieval catheter 200 includes a catheter shaft210 and a retrieval magnet 220 disposed at a distal end of a shaft orwire 222. Retrieval catheter 200 also includes a snare 230 coupled toshaft 222. With retrieval catheter 200 adjacent magnets 120, 120′,retrieval magnet 220 is extended from catheter shaft 210 by distallyextending shaft 222 or retracting catheter shaft 210, as shown in FIG.7. Retrieval magnet 220 is magnetically coupled to magnets 120, 120′.Snare 230 is then extended over magnets 120, 120′, 220 and tightened.Snare 230 is a pre-shaped loop formed using nitinol or other shapememory material to have an opening large enough to easily clear themagnets 120, 120′, 220. Similar to tether 124 described above, snare 230is a wire with a first end disposed at a proximal end (not shown) of atube 240. The wire extends distally within tube 240 and out of a distalend of tube 240, forming a loop and extending back proximally to asecond end also disposed at a proximal end of tube 240. Tube 240 isadvanced from the distal end of the catheter shaft 210 such that snare230 extends distally beyond the magnets 120, 120′, 220, as shown in FIG.7A. Pulling both ends of the proximal end of the wire forming snare 230closes snare 230 around tethers 119, 119′ as shown in FIG. 7B. Shaft 222and tube 240 are then simultaneously retracted proximally, pullingmagnets 120, 120′, 220 and filters 110, 110′ into catheter shaft 210, asshown in FIGS. 7C and 8. Catheter shaft 210, with filters 110, 110′disposed therein, may then be removed from the body. Alternatively, oncefilters 110, 110′ removed from the branch vessels, shaft 210 may beadvanced distally over filters 110, 110′ and then catheter 210 withfilters 110, 110′ disposed therein may be removed from the body.

Embolic protection device 100 as described above and used in the methoddescribed in FIGS. 3-8 may be modified for various reasons. For example,and not by way of limitation, different filters and delivery devices maybe used. In another non-limiting example, it may be desirable to ensurethat the magnetic connection between magnets 120, 120′ is properly madea sufficiently secure to prevent filters 110, 100′ from movingdownstream.

FIG. 10 shows an embodiment of a modification to embolic protectiondevice 100 to ensure that magnets 120, 120′ are properly coupled beforereleasing wire loop 122 from tether 124. In particular, a releasablesnare 126 extends from sheath 108 distally past magnet 120 and aroundtether 119. Snare 126 is in this position during delivery of embolicprotection device 100 and retraction of sheath 108 to deploy filterassembly 102. After magnets 120, 120′ have been magnetically coupledtogether, wire loop 122 is released from tether 124, as described above.However, if the magnetic attraction between magnets 120, 120′ is notsufficient, or for some other reason the magnets 120, 120′ becomedetached, snare 126 catches magnet 120, preventing release of filterassembly 102 from sheath 108. Snare 126 can be retracted to recapturemagnet 120 and filter assembly 102 into sheath 108. If the magneticconnection between magnets 120, 120′ is sufficient, snare 126 isreleased and the procedure proceeds as described above. Snare 126 may besimilar to snare 230 described above with respect to FIGS. 7A-7C ortether 124 described above. In such an embodiment, if the magneticattraction between magnets 120, 120′ is sufficient, one end of the wireforming snare 126 is pulled proximally until the second end extendsdistally and then back proximally to withdraw the wire from the body.Alternatively, snare 126 may include a slip-knot 127 as shown in FIG.10. In such an embodiment, if the magnetic connection between magnets120, 120′ is sufficient, proximal end of the wire of snare 126 is pushedto enlarge the size of the loop of snare 126. The wire is then pulledsuch that snare 126 extends proximally over magnet 120 and is removedfrom the body through sheath 108. Each embolic protection device 100,100′ can have this feature, or only one of the two can have it. If onlyone includes this feature, its wire loop 122 and tether 124 should bereleased first.

Other devices may also be used to ensure a strong connection betweenmagnets 120, 120′. For example, the magnetic connection can besupplanted with a mechanical connection. For example, and not by way oflimitation, FIGS. 11 and 12 show a modification to magnet 120 to helpensure a secure connection to magnet 120′. In particular, a lockingmechanism 128 is coupled to magnet 120. Locking mechanism 128 includes afirst wall 129 with second and third walls 130, 131 extendingsubstantially perpendicular to first wall 129 and parallel to each otherto form three sides of a rectangle. Magnet 120 is coupled to an insidesurface of first wall 129. Extending from an end of second wall 130opposite first wall 129 is a latch 132. Latch 132 extends toward theinterior of the three-sided rectangle formed by first, second, and thirdwalls 129, 130, 131. In the embodiment shown, latch 132 also extendstowards first wall 129. Similarly, extending from an end of third wall131 opposite first wall 129 is a latch 133. Latch 133 extends toward theinterior of the three-sided rectangle formed by first, second, and thirdwalls 129, 130, 131. In the embodiment shown, latch 133 also extendstowards first wall 129. Wire loop 122, described above, is coupled to anoutside surface of second wall 130 and tether 119 is coupled to anoutside surface of third wall 131, as shown in FIG. 11. Accordingly,filter assembly 102 (not shown in FIGS. 11-12) is coupled tether 119opposite locking mechanism 128. When locking assembly 128 with magnet120 disposed therein is located adjacent to magnet 120′, magnets 120 and120′ are attracted to each other such that magnet 120 enters into thethree-sided rectangle formed by walls 129, 130, 132 from the open-endthereof, as shown in FIG. 12. Latches 132, 133 prevent magnet 120′ fromexiting the three-sided rectangle, thereby preventing detachment ofmagnets 120, 120′. In FIG. 12, wire loop 122′ is not shown, but isdisposed between magnets 120, 120′.

FIGS. 39-41 show locking mechanism 128 in another configuration. Inparticular, in the embodiment of FIGS. 39-41, magnets 120, 120′ aredisposed side-by-side in locking mechanism 128, instead of one in frontof the other. As can be seen in FIGS. 40 and 41, when magnets 120, 120′are disposed within locking mechanism 128, both magnets abut againstfirst wall 129. Magnet 120 also abuts against third wall 131 and magnet120′ also abuts against second wall 130. As shown in FIG. 39, magnet 120is disposed within locking mechanism 128 when embolic protection device100 is delivered to the implantation site. Magnet 120 may be attached tolocking mechanism any manner know to those skilled in the art, such asby an adhesive of mechanical connection. Also, because magnet 120 isattached to locking mechanism 128, latch 133 may be excluded in thisembodiment. Magnet 120′ is attracted to magnet 120 such that adjacentsides are attracted to each other, as shown in FIGS. 40 and 41.

FIGS. 13-14 show an embodiment of embolic protection devices 100, 100′with modifications to keep magnets 120, 120′ out of the aortic arch 14so that magnets 120, 120′ do not interfere with devices extendingthrough the aorta 10, such as devices for a TAVI procedure. Inparticular, tethers 119, 119′ of embolic protection devices 100, 100′are of a length such that magnets 120, 120′ do not extend into the aorta10. In order to couple the filters 110, 110′ to each other to preventdownstream migration, a connecting device 134 couples magnet 120 ofembolic protection device 100 to magnet 120′ of embolic protectiondevice 100′. In particular, as shown in FIG. 13, embolic protectiondevice 100 includes filter assembly 102, tether 119, and magnet 120.Additionally, a first magnet 136 of connecting device 134 is coupled tomagnet 120. A connecting wire 135 is coupled to first magnet 136 at afirst end of wire 135. Disposed at a second end of connecting wire 135is a second magnet 138. Second magnet 138 is coupled to wire loop 122and tether 124, as described above with respect to FIGS. 1 and 9.Embolic protection device 100′ is as described above with respect toFIGS. 1 and 9, except that tether 119 is of a length that it does notextend to aorta 10 when filter assembly 102 is deployed within leftcommon carotid artery 22. With sheaths 108, 108′ retracted to deployfilters 110, 110′, respectively, sheaths 108, 108′ are manipulated suchthat second magnet 138 is disposed adjacent magnet 120′, as shown inFIG. 13. When a magnetic connection is established between second magnet138 and magnet 120′ of embolic protection device 100′, wire loop 122attached to second magnet 138 may be disconnected from tether 124 andwire loop 122′ attached to magnet 120′ may be disconnected from tether124′, as described above. Sheath 108, 108′ are removed from the aorta,leaving filter assemblies 102, 102′ and connecting device 134, as shownin FIG. 14. With the filters deployed as shown in FIG. 16, proceduresfor the aortic valve, such as TAVI or valvuloplasty, may access theaortic valve area through the aortic arch 14 with minimal interferencefrom the embolic protection devices. After the completion of theprocedures, filter assemblies 102, 102′ may be recaptured as explainedabove with respect to FIGS. 7-8.

FIGS. 15-17 show schematically an embodiment of embolic protectiondevices 100, 100′. Embolic protection devices 100, 100′ are similar toembolic protection device 100 described above with respect to FIGS. 1-9.However, tether 119 of embolic protection device 100 is relativelyshorter than described above such that magnet 120 does not extend intoaorta 10. Further, tether 119′ of embolic protection device 100′ isrelatively longer such that tether 119′ extends from left common carotidartery 22, into aortic arch 14, and into brachiocephalic artery 20, asshown in FIG. 16. Accordingly, after sheaths 108, 108′ have beenretracted to deploy filters 110, 110′ and expose magnets 120, 120′, asdescribed above with respect to FIGS. 3-4, the embolic protectiondevices 100, 100′ are maneuvered such that magnets 120, 120′ aresufficiently close to each other magnetically couple to the each other,as shown in FIG. 15. Once magnets 120, 120′ are coupled to each other,wire loops 122, 122′ are disconnected from tethers 124, 124′,respectively, as described above. Sheaths 108, 108′ with tethers 124,124′ may be retracted out of the body, leaving filter assembly102/filter 110 deployed within the brachiocephalic artery 20, and filterassembly 102′/filter 110′ deployed within left common carotid artery 22,as shown in FIG. 16. Further, the filter assemblies 102, 102′ arecoupled together via tethers 119, 119′, but only tether 119′ extendsinto aorta 10, and magnets 120, 120′ are both disposed in thebrachiocephalic artery 20, as also shown in FIG. 16. With the filtersdeployed as shown in FIG. 16, procedures for the aortic valve, such asTAVI or valvuloplasty, may access the aortic valve area through theaortic arch 14 with minimal interference from the embolic protectiondevices. It would be understood by those skilled in the art thatalthough FIGS. 15 and 16 show a short tether 119 associated with thefilter 110 deployed in the brachiocephalic artery 20 and a long tether119′ associated with the filter 110′ deployed in the left common carotidartery, the locations can be reversed such that the long tether extendsfrom the brachiocephalic artery 20, into the aortic arch 14, and intothe left common carotid artery 22, where the magnets 120, 120′ arecoupled to each other.

After the procedure is completed and the procedure devices have beenremoved, the filters 110, 110′ may be removed. In order to remove thefilters, a retrieval catheter 200′ is advanced adjacent the location ofthe magnets 120, 120′, as described above with respect to FIG. 7.Retrieval catheter 200′ includes a catheter shaft 210′ and a retrievalmagnet 220′ disposed at a distal end of a shaft or wire 222′. Retrievalcatheter 200′ also includes a snare 230′ coupled to shaft 222′. Withretrieval catheter 200′ maneuvered such that it is adjacent magnets 120,120′, retrieval magnet 220′ is extended from catheter shaft 210′ bydistally extending shaft 222′ or retracting catheter shaft 210′, asdescribed above with respect to FIG. 7. However, due to the location ofmagnets 120, 120′, this recapture will take place within one of thebrachiocephalic artery 20 or left common carotid artery 22, depending onwhere the magnets 120, 120′ are coupled to each other. Retrieval magnet220′ is magnetically coupled to magnets 120, 120′. Snare 230′ is thenextended over magnets 120, 120′, 220 and tightened, as described abovewith respect to FIGS. 7A-7C. Shaft 222′ is then retracted proximally,pulling magnets 120, 120′, 220′ and filters 110, 110′ into cathetershaft 210′, as shown in FIG. 17. Catheter shaft 210′, with filters 120,120′ disposed therein, may then be removed from the body. Further, asshown in FIG. 17, because tether 119′ is longer than tether 119, whenthe filters 110, 110′ are retracted into catheter shaft 210′, thefilters 110, 110′ enter catheter shaft 210′ sequentially or serially,rather than simultaneously or in parallel as shown in FIGS. 7-8.Accordingly, catheter shaft 210′ utilized with the embodiment of FIGS.15-17 may be smaller in diameter than catheter shaft 210 described abovewith respect to FIGS. 7-8. Further, although FIGS. 15 and 16 show themagnets 120, 120′ both disposed in a single branch artery, it would beunderstood by those skilled in the art that the tethers 119, 119′ can beof different lengths with the magnets 120, 120′ both disposed in theaorta (main vessel). In such an embodiment the different length tethers119, 119′ provide the benefit that filters 110, 110′ enter cathetershaft 210′ sequentially or serially, rather than simultaneously or inparallel, as described above.

In another embodiment shown in FIG. 18, tethers 119, 119′ of embolicprotection devices 100, 100′ are replaced with spring tethers 140, 140′.Spring tethers 140, 140′ may be any material or shape such that eachtether 140, 140′ tends to gather or shorten toward its respective filter110, 110′. In other words tethers 140, 140′ provide a force in thedirection of arrows 142, 142′. This shortening force may be provided bymaking tether 140, 140′ out of a shape memory material that tends toreturn to its original coiled shape, or by creating a spring force bythe shape of the tether 140, 140′, such as a commonly known springshape. The magnetic attraction between magnets 120, 120′ is greater thanthe shortening forces 142, 142′ such that magnets 120, 120′ remaincoupled to each other, However, the shortening forces 142, 142′ take upany slack in tethers 140, 140′ such that tethers 140, 140′ do not hangor extend into the middle of aorta 10, thereby possibly interfering withprocedure devices extending through the aorta 10. Thus, tethers 140,140′ and magnets 120, 120′ are pulled against the aortic wall 30 betweenthe brachiocephalic artery 20 and the left common carotid artery 22, asshown in FIG. 18. FIG. 18 also shows the magnets 120, 120′ may beC-shaped. However, as would be understood by those skilled in the art,magnets 120, 120′ of this embodiment or any of the embodiments describedherein, may be any shape suitable for coupling filter assemblies 102,102′ to each other.

In the embodiments described above with respect to FIGS. 1-18, thetethers described may be retractable and extendable tethers.Accordingly, instead of a long tether and a short tether as describedwith respect to FIGS. 15-17, one or both of the tethers 119, 119′ may beextendable and retractable. FIG. 38 shows tether 119 including a reel160. Reel 160 includes a housing 162 with a spring 164 disposed withinthe housing 162. Tether 119 is wrapped around spring 164. A secondarytether 166 couples reel 160 to filter assembly 102. Spring 164 retractstether 119 in the direction of spring 164, as shown by the arrow in FIG.38. The retraction force of spring 164 is not sufficient to overcome theattractive magnetic force between magnets 120, 120′. Accordingly, thelength of the extendable and retractable tether can be extended suchthat the magnets can be disposed in the same artery, and the tether canbe retracted to take up any slack in the tether such that tethers do nothang or extend into the middle of the aorta 10, as described above withrespect to FIG. 18.

FIG. 19 is a schematic illustration of an embolic protection device 300used in conjunction with embolic protection devices 100, 100′ describedabove. As shown in FIG. 19, embolic protection devices 100, 100′ aredeployed in the brachiocephalic artery 20 and the left common carotidartery 22, respectively, as described above. Accordingly, magnets 120,120′ connecting filters 110, 110′ to each other are disposed withinaorta 10 in the region of the aortic arch 14. An additional embolicprotection device 300 is deployed in the aorta 10 and magneticallycoupled to magnets 120, 120′, as shown in FIG. 19. As shown in FIG. 19A,an embodiment of embolic protection device 300 includes a filter 302 anda magnet 304 coupled to filter 302. Filter 302 includes a distal end 306and a proximal end 308. Proximal end 308 of filter 302 is attached to anouter shaft 312 at a connection 310 such that proximal end 308 does notmove relative to outer shaft 312. An inner shaft 314 is disposed throughouter shaft 312 and is slidable relative thereto. Distal end 306 offilter 302 is coupled to inner shaft 314, such as by connecting struts316. Sliding inner shaft 314 relative to outer shaft 312 opens andcloses filter 302. Further, inner shaft 302 is sized to permit aprocedural catheter 320, such as for a TAVI procedure, to be deliveredthrough a lumen thereof, as shown in FIG. 19. Although a particularembodiment of embolic protection device 300 has been described, thoseskilled in the art would recognize that any filter device that permitsprocedural catheter 320 to pass therethrough could be used. For example,and not by way of limitation, filter 302 may be incorporated as part ofprocedural catheter 320. In one non-limiting example, filter 302 may bea self expanding filter, inner shaft 314 may be eliminated, and distalend 306 of filter 302 may be slidably coupled to procedural catheter320. Further, the location of magnet 304 on filter 302 may be alteredsuch that the location of filter 302 may be altered. For example, andnot by way of limitation, magnet 304 may be disposed at the distal endof filter 302 such that the filter 302 is disposed further downstream inthe aorta 10. The location of magnets 120, 120′ may also be altered tochange the location of filter 302. Other modifications may be made, asknown to those skilled in the art.

As shown in FIG. 19, after embolic protection devices 100, 100′ havebeen deployed, embolic protection device 300 is advanced into the aorticarch 14 and deployed such that magnet 304 of filter 302 is magneticallycoupled to magnets 120, 120′. Although one magnet 304 is shown, multiplemagnets 304 may be distributed around the circumference of filter 302such that a particular orientation of filter 302 is not required. Uponcompletion of the procedure filters 110, 110′ may be retracted withfilter 302 due to the magnetic connection between magnets 120, 120′ andmagnet 304.

FIGS. 20-21 show schematically modifications to embolic protectiondevice 100 and retrieval catheter 200. In particular, embolic protectiondevice 100 as shown in FIG. 21 includes a plurality of magnets 150coupled to filter 110. Magnets 150 may preferably be located distally ofopenings 114 and/or at the largest diameter of filter 110. Magnets 150are disposed around the circumference of filter 110. In one embodiment,four magnets are used, although more or less may be used. Similarly, adistal end 212 of catheter shaft 210 of retrieval catheter 200 includesa plurality of magnets 240 disposed around the periphery thereof. In oneembodiment, four magnets 240 are disposed at distal end 212 of cathetershaft 210. However, those skilled in the art would understand that moreor less magnets 240 can be used. Further, in an embodiment, the entiredistally facing surface of catheter shaft 210 may be a magnet or may bemagnetized. Accordingly, when embolic protection device 100 is retractedtowards catheter shaft 210, as described above with respect to FIGS.7-8, magnets 150 on filter 110 and magnets 240 on distal end 212 ofcatheter shaft 210 are attracted to each other, magnetically couplingcatheter shaft 210 and filter 110, as shown in FIG. 22. Catheter shaft210 can then be removed from the body, with filter 110 coupled to distalend 212 thereof. In some instances with certain filters, embolic debrismay be released from filters when the filters are collapsed for removalfrom the body. By not collapsing filter 110 for removal from the body,embolic debris is not released from filter 110. Alternatively, after thefilter 110 is magnetically coupled to catheter shaft 210, the cathetermay be aspirated by providing a suction force to remove debris from thefilter 110. The filter 110 may then be collapsed into catheter shaft 210and catheter shaft 210 and filter 110 may be removed from the body.

FIGS. 23-25 schematically show an embodiment of an embolic protectiondevice 400 for deployment within a vessel 420. Embolic protection device400 includes a filter assembly 402, a distal tip 404, an inner shaft406, and an outer shaft or sheath 408. Distal tip 404 may integral withinner shaft 406 or may be a distal end of a guidewire extending througha lumen of inner shaft 406. Filter assembly 402 includes a filter 410having a distal end 411 coupled to a distal magnet 412 and a proximalend 413 coupled to a proximal magnet 414. Distal magnet 412 is coupledto inner shaft 406 such that distal magnet 412 does not slide relativeto inner shaft 406. Proximal magnet 414 is slidably coupled to innershaft 406 such that proximal magnet 414 can slide relative to innershaft 406. Proximal magnet 414 and distal magnet 412 are oriented suchthat there is a magnetic attraction force between them, as indicated bythe magnetic pole indications in FIG. 23.

Filter 410 may be any material suitable for use in a filter. Forexample, and not by way of limitation, stainless steel, nitinol,polymers, or other filaments may be used to form filter 410. Asdescribed in more detail below, filter 410 need not be a shape memorymaterial due to the use of magnets 412, 414 to open and close filter410.

As shown in FIG. 23, embolic protection device 400 is in a delivery orcompressed configuration with sheath 408 extended over filter 410. Theradial force from sheath 408 overcomes the magnetic attraction forcebetween magnets 412, 414 such that filter 410 remains in the compressedconfiguration. When embolic protection device 400 is advanced to adesired deployment location within vessel 420, sheath 408 is retracted,as shown in FIG. 24. With sheath no longer applying radial pressure onfilter 410, the magnetic attraction force between magnets 412, 414 causeproximal magnet 414 to slide towards distal magnet 412, therebyexpanding filter 410, as shown in FIG. 24. Proximal magnet 414 stopsmoving towards distal magnet 412 when filter is deployed. Stoppingfilter 410 from expanding beyond a desired amount can be accomplished inseveral ways. In one embodiment, the magnetic attraction force betweenmagnets 412, 414 is designed to be less than the radial force of vessel420 such that vessel 420 stops expansion of filter 410. In anotherembodiment, design features of filter assembly 402 stop filter 410 fromover-expanding. In one non-limiting example, a stop (not shown) isprovided on inner shaft 406 to prevent proximal magnet 414 from slidingpast a desired location. In another non-limiting example, forces fromfilter 410 prevent proximal magnet from sliding past a desired locationof inner shaft 406. In another non-limiting example, filter assembly 402is designed such that filter 410 is deployed when proximal magnet 414reaches distal magnet 412 such that proximal magnet is allowed to slideall the way to distal magnet 412. Those skilled in the art wouldrecognize other methods to assure the proper deployment size of filter410.

After deployment of filter assembly 402, sheath may be removed and aprocedure upstream of filter 410 may be performed. Filter 410 captureemboli flowing downstream of the procedure, as discussed above. When theprocedure for which the embolic protection device 400 was utilized iscompleted, a retrieval device 420 is utilized to collapse filterassembly 402 from its radial expanded or deployed configuration to theradially compressed configuration. In an embodiment, retrieval device430 includes a retrieval magnet 434 disposed at a distal end of aretrieval shaft 432, as shown in FIG. 25. Inner shaft 406 may bebackloaded into retrieval shaft 432 and retrieval shaft 432 is advancedover inner shaft 406, as shown in FIG. 25. Retrieval magnet 434 isoriented such that there is a magnetic attraction force betweenretrieval magnet 434 and proximal magnet 414, as represented by themagnetic pole markings in FIG. 25. Retrieval magnet 434 is configured toapply a larger attraction force on proximal magnet 414 than theattraction force between proximal magnet 414 and distal magnet 412.Accordingly, when retrieval magnet 434 is advanced adjacent to proximalmagnet 414, the attraction force therebetween magnetic couples retrievalmagnet 434 and proximal magnet 414. Retraction of retrieval magnet 434causes proximal magnet 414 to move proximally to radially compressfilter 410, as shown in FIG. 25. As would be understood by those skilledin the art, retrieval magnet 434 and proximal magnet 414 may be coupledto each other or the attraction force between the two magnets may besufficient such that advancing retrieval magnet adjacent proximal magnet414 is sufficient to cause proximal magnet 414 to move towards retrievalmagnet 434 to radially compress filter 410. Retrieval shaft 432 may beretraced proximally to capture radially compressed filter 410 intosheath 408 or a separate retrieval shaft (not shown). Sheath 408 or sucha retrieval catheter may then be removed from the body.

FIGS. 26-28 show schematically an embolic protection device 500 and amethod of deploying and retrieving embolic protection device 500. FIGS.26-28 do not show embolic protection device 500 deployed within a vesselfor clarity. However, it would be understood by those skilled in the artthat embolic protection device 500 can be deployed within a vessel, suchas vessel 420 shown schematically in FIGS. 23-25. Embolic protectiondevice 500 includes a filter assembly 502, a distal tip 504, an innershaft 506, and an outer shaft or sheath 508. Distal tip 504 may integralwith inner shaft 506 or may be a distal end of a guidewire extendingthrough a lumen of inner shaft 506. Filter assembly 502 includes afilter 510 having a distal end 511 coupled to a distal magnet 512, anintermediate portion 513 coupled to a proximal magnet 514, and aproximal portion 521 coupled to a proximal connector 522. Distal magnet512 is coupled to inner shaft 506 such that distal magnet 512 does notslide relative to inner shaft 506. Proximal magnet 514 is slidablycoupled to inner shaft 506 such that proximal magnet 514 can sliderelative to inner shaft 506. Proximal magnet 514 and distal magnet 512are oriented such that there is an attractive magnetic forcetherebetween, as indicated by the magnetic pole indications in FIG. 26.Proximal connector 522 is slidably coupled to inner shaft 506 such thatproximal connector 522 can slide relative to inner shaft 506. A shaft524 is coupled to proximal connector 522 and is slidable relative toinner shaft 506.

Filter 510 further includes a distal mesh of filter 516 and a proximalmesh or filter 518. In one embodiment, distal filter 516 is a fine meshfilter such as a filter having pores in the range of 10-100 microns andproximal filter 518 is a coarse mesh such as a filter having poreslarger than 100 microns. However, as known to those skilled in the artdifferent sizes may be utilized depending on the intended location offilter 510 and the type of procedure for which filter 510 is beingutilized. Accordingly, distal end 511 of filter 510 is a distal end ofdistal filter 516 and proximal end 513 of filter 510 is a proximal endof proximal filter 518. Proximal and distal filters 518, 516 meet at anintermediate portion of filter 510, which generally coincides with aproximal end of distal filter 516 and a distal end of proximal filter518, as shown in FIG. 26. Filter assembly 502 further includes supportarms or tethers 520 extending from intermediate portion 526 of filter510 to proximal connector 522, as shown in FIG. 26. Although only twosupport arms are shown in FIG. 26 due to the view used, those skilled inthe art would appreciate that more support arms may be utilized. Inparticular, three or four support arms 520 are preferable. As shown inFIG. 26, proximal ends of support arms 520 are the proximal end 521 offilter assembly 502 and are coupled to proximal connector 522.

Filters 516, 518 may be any material suitable for use in a filter. Forexample, and not by way of limitation, stainless steel, nitinol,polymers, or other filaments may be used to form filters 516, 518. Asdescribed in more detail below, filter 510 need not be a shape memorymaterial due to the use of magnets 512, 514 and slidable connector 522to open and close filter 510.

As shown in FIG. 26, embolic protection device 500 is in a delivery orcompressed configuration with sheath 508 extended over filter 510, andproximal magnet 514 spaced apart from distal magnet 512 such thatproximal filter 518 and distal filter 516 are disposed longitudinallyrelative to each other, or end-to-end. In other words, as shown in FIG.26, in the delivery configuration, proximal magnet 514 and proximal end513 of proximal filter 518 are disposed proximal of intermediate portion526 (i.e. proximal end distal filter 516). The radial force from sheath508 overcomes the magnetic attraction force between magnets 512, 514such that filter 510 remains in the delivery configuration.

When embolic protection device 500 is advanced to a desired deploymentlocation within a vessel, sheath 508 is retracted, as shown in FIG. 27.With sheath 508 no longer applying radial pressure on filter 510, themagnetic attraction force between magnets 512, 514 causes proximalmagnet 514 to slide towards distal magnet 512, thereby expanding filter510, as shown in FIG. 27. Proximal magnet 514 stops moving towardsdistal magnet 512 when filter 510 is deployed. Stopping filter 510 fromexpanding beyond a desired amount can be accomplished in several ways.In one embodiment, the magnetic attraction force between magnets 512,514 is designed to be less than the radial force of the vessel such thatthe vessel stops expansion of filter 510. In another embodiment, designfeatures of filter assembly 502 stop expansion of filter 510. In onenon-limiting example, a stop (not shown) is provided on inner shaft 506to prevent proximal magnet 514 or proximal connector 522 from slidingpast a desired location. In another non-limiting example, forces fromfilter 510 prevent proximal magnet 514 from sliding past a desiredlocation of inner shaft 506. Those skilled in the art would recognizeother methods to assure the proper deployment size of filter 510.

After filter assembly 502 is deployed, sheath 508 may be removed (notshown) and a procedure upstream of filter 510 may be performed. Withfilter assembly 502 deployed as shown in FIG. 27, blood flow through thevessel passes through proximal (coarse mesh) filter 518 and then distal(fine mesh) filter 516. Accordingly, large emboli are captured byproximal filter 518 and smaller emboli are captured by distal filter516.

When the procedure for which the embolic protection device 500 wasutilized is completed, filter assembly 502 is radially compressed into aretrieval configuration, shown in FIG. 28. Filter assembly 502 isradially compressed by pulling shaft 524, which is coupled to slidableconnector 522. Because of the magnetic attraction between magnets 512,514, retraction of shaft 524 does not cause proximal magnet 514 to slideproximally. Instead, as shown in FIG. 27, intermediate portion 526 offilter 510, where distal filter 516 and proximal filter 518 meet, ispulled proximally and towards inner shaft 506 by support arms 520. Thismovement captures the emboli within filter 510 as distal (fine mesh)filter 516 provides a distal block and a proximal block to preventemboli from escaping filter 510. Filter assembly 502 may then be pulledinto sheath 508 or a separate recapture sheath, or sheath 508 or aseparate recapture sheath may be pushed distally over filter assembly502.

FIGS. 29-31 show schematically an embolic protection device 600 and amethod of deploying and retrieving embolic protection device 600. FIGS.29-31 do not show embolic protection device 600 deployed within a vesselfor clarity. However, it would be understood by those skilled in the artthat embolic protection device 600 can be deployed within a vessel, suchas vessel 420 shown schematically in FIGS. 23-25. Embolic protectiondevice 600 includes a filter assembly 602, a distal tip 604, an innershaft 606, and an outer shaft or sheath 608. Distal tip 604 may beintegral with inner shaft 606 or may be a distal end of a guidewireextending through a lumen of inner shaft 606. Similar to filter assembly502, filter assembly 602 includes a filter 610 having a distal end 611coupled to a distal magnet 612, an intermediate portion 613 coupled to aproximal magnet 614, and a proximal portion 621 coupled to a proximalconnector 622. Distal magnet 612 is coupled to inner shaft 606 such thatdistal magnet 612 does not slide relative to inner shaft 606. Proximalmagnet 614 is slidably coupled to inner shaft 606 such that proximalmagnet 614 can slide relative to inner shaft 606. Proximal magnet 614and distal magnet 612 are oriented such that there is a repulsivemagnetic force therebetween, as indicated by the magnetic poleindications in FIG. 29. Proximal connector 622 is slidably coupled toinner shaft 606 such that proximal connector 622 can slide relative toinner shaft 606. A shaft 624 is coupled to proximal connector 622 and isslidable relative to inner shaft 606.

Filter 610 further includes a distal mesh of filter 616 and a proximalmesh or filter 618. In one embodiment, distal filter 616 is a fine meshfilter such as a filter having pores in the range of 10-100 microns andproximal filter 618 is a coarse mesh such as a filter having poreslarger than 100 microns. However, as known to those skilled in the artdifferent sizes may be utilized depending on the intended location offilter 610 and the type of procedure for which filter 610 is beingutilized. Accordingly, distal end 611 of filter 610 is a distal end ofdistal filter 616 and proximal end 613 of filter 610 is a proximal endof proximal filter 618. Proximal and distal filters 618, 616 meet at anintermediate portion 626 of filter 610, which generally coincides with aproximal end of distal filter 616 and a distal end of proximal filter618, as shown in FIG. 30. Filter assembly 602 further includes supportarms or tethers 620 extending from intermediate portion 626 of filter610 to proximal connector 622, as shown in FIGS. 29-31. Although onlytwo support arms are shown in the figures due to the view used, thoseskilled in the art would appreciate that more support arms may beutilized. In particular, three or four support arms 620 are preferable.As shown in FIGS. 29-31, proximal ends of support arms 620 are theproximal end 621 of filter assembly 602 and are coupled to proximalconnector 622.

Filters 616, 618 may be any material suitable for use in a filter. Forexample, and not by way of limitation, stainless steel, nitinol,polymers, or other filaments may be used to form filters 616, 618. Asdescribed in more detail below, filter 610 need not be a shape memorymaterial due to the use of magnets 612, 614 and slidable connector 622to open and close filter 610.

As noted above, embolic protection device 600 is similar to embolicprotection device 500 of FIGS. 26-28. However, as shown in FIG. 26,embolic protection device 600 in a delivery or radially compressedconfiguration with sheath 608 extended over filter 610, proximal magnet614 is disposed nearer to distal magnet 612 than intermediate portion626 is to distal magnet 612. Accordingly, the delivery configuration ofembolic protection device 600 is different from the deliveryconfiguration of embolic protection device 500. Further, as noted above,proximal and distal magnets 614, 612 as oriented such that there is arepulsive magnetic force therebetween. Accordingly, in the deliveryconfiguration of FIG. 29, radial force from sheath 608 overcomes therepulsive magnetic force between magnets 612, 614 such that filter 610remains in the delivery configuration.

When embolic protection device 600 is advanced to a desired deploymentlocation within a vessel, sheath 608 is retracted, as shown in FIG. 30.With sheath 608 no longer applying radial pressure on filter 610, therepulsive magnetic force between magnets 612, 614 (as indicated byarrows A) causes proximal magnet 614 to slide away from distal magnet612, thereby expanding filter 610, as shown in FIG. 30. Proximalconnection 622 also moves towards distal magnet 612 as filter 610radially expands (as indicated by arrow B). Proximal magnet 614 stopsmoving away from distal magnet 612 when filter 610 is deployed. Stoppingproximal magnet 614 from moving away from distal magnet 612 beyond adesired amount can be accomplished in several ways. In one embodiment,the repulsive magnetic force between magnets 612, 614 is designed to beless than the radial force of the vessel such that the vessel stopsexpansion of filter 610. In another embodiment, design features offilter assembly 602 and the amount of the repulsive magnetic force stopexpansion of filter 610. In one non-limiting example, the repulsivemagnetic force between magnets 612, 614 is such that when proximalmagnet 614 reaches a certain distance away from distal magnet 612, therepulsive force is no longer large enough to cause proximal magnet 614to move. In another non-limiting example, a stop (not shown) is providedon inner shaft 606 to prevent proximal magnet 614 or proximal connector622 from sliding past a desired location. In another non-limitingexample, forces from filter 610 prevent proximal magnet 614 from slidingpast a desired location of inner shaft 606. Those skilled in the artwould recognize other methods to assure the proper deployment size offilter 610.

After filter assembly 602 is deployed, sheath 608 may be removed (notshown) and a procedure upstream of filter 610 may be performed. Withfilter assembly 602 deployed as shown in FIG. 30, blood flow through thevessel passes through proximal (coarse mesh) filter 618 and then distal(fine mesh) filter 616. Accordingly, large emboli are captured byproximal filter 618 and smaller emboli that pass through proximal filter618 are captured by distal filter 616.

When the procedure for which the embolic protection device 600 wasutilized is completed, filter assembly 602 is radially compressed into aretrieval configuration, shown in FIG. 31. Filter assembly 602 isradially compressed by pulling shaft 624, which is coupled to slidableconnector 622. This pulling force overcomes the repulsive magnetic forcebetween proximal and distal magnets 614, 612 magnets such that proximalconnection 622 moves proximally as indicated by arrow C and proximalmagnet 614 moves distally as indicated by arrow D, as shown in FIG. 31.As also shown in FIG. 31, intermediate portion 626 moves proximally andtowards inner shaft 606 to radially compress filter 610. Filter assembly602 may then be pulled into sheath 608 or a separate recapture sheath,or sheath 608 or a separate recapture sheath may be pushed distally overfilter assembly 602.

FIGS. 32-34 show schematically an embolic protection device 700 and amethod of deploying and retrieving embolic protection device 700. FIGS.32-34 do not show embolic protection device 700 deployed within a vesselfor clarity. However, it would be understood by those skilled in the artthat embolic protection device 700 can be deployed within a vessel, suchas vessel 420 shown schematically in FIGS. 23-25. Embolic protectiondevice 700 includes a filter assembly 702, a distal tip 704, an innershaft 706, and an outer shaft or sheath 708. Distal tip 704 may beintegral with inner shaft 706 or may be a distal end of a guidewireextending through a lumen of inner shaft 706.

Filter assembly 702 includes a filter 710 having a distal end 711coupled to a distal magnet 712 and a proximal end 717 coupled to aproximal magnet 718. Distal magnet 712 is coupled to inner shaft 706such that distal magnet 712 does not slide relative to inner shaft 706.Proximal magnet 718 is slidably coupled to inner shaft 706 such thatproximal magnet 718 can slide relative to inner shaft 706. Filterassembly further includes two intermediate magnets 714, 716 disposedbetween proximal magnet 718 and distal magnet 712. Intermediate magnets714, 716 are coupled to inner shaft 706 such that intermediate magnets714, 716 can slide relative to inner shaft 706. A first flexible shaftor bellows 720 is disposed between distal magnet 712 and intermediatemagnet 714. A second flexible shaft or bellow 722 is disposed betweenintermediate magnet 714 and intermediate magnet 716, and a thirdflexible shaft or bellows 724 is disposed between intermediate magnet716 and proximal magnet 718, as shown in FIG. 33. Bellows 720, 722, 724are disposed around inner shaft 706 such that there are annular orinflations lumens 721, 723, 725 between inner shaft 706 and each of thebellows 720, 722, 724. Further, magnets 714, 716, 718 are coupled toinner shaft 706 such that a lumen extends through magnets 714, 716, 718between inner shaft 706 and each magnet 714, 716, 718. Further, a shaft726 disposed around inner shaft 706 extends proximally from proximalmagnet 718 to a proximal end of embolic protection device 700. Anannular or inflation lumen 728 is disposed between inner shaft 706 andshaft 726. Inflation lumen 728 is fluidly connected to inflation lumens721, 723, 725. Distal magnet 712 is coupled to inner shaft 706 such thatfluid from inflation lumen 721 cannot pass therethrough.

Magnets 712, 714, 716, 718 are oriented such that there is an attractivemagnetic force between proximal magnet 718 and intermediate magnet 716,between intermediate magnet 716 and intermediate magnet 714, and betweenintermediate magnet 714 and distal magnet 712, as indicated by themagnetic pole indications in FIG.

Filter 710 as shown in FIGS. 32-34 is a single mesh filter. However,those skilled in the art would recognize that a dual mesh filter, suchas the filters described with respect to 26-28 and 29-31 could also beused with the embolic protection device 700 of FIGS. 32-34. Filter 710may be a mesh filter having pores in the range of 10-400 microns.However, as known to those skilled in the art different sizes may beutilized depending on the intended location of filter 710 and the typeof procedure for which filter 710 is being utilized. Filter 710 may beany material suitable for use in a filter. For example, and not by wayof limitation, stainless steel, nitinol, polymers, or other filamentsmay be used to form filter 710. As described in more detail below,filter 710 need not be a shape memory material due to the use of magnets712, 714, 716, 718 and bellows 720, 722, 724 to open and close filter710.

As shown in FIG. 32, embolic protection device 700 is in a delivery orradially compressed configuration with sheath 708 extended over filter710. As shown in FIG. 32, magnets 712, 714, 716, 718 are spaced fromeach other and bellows 720, 722, 724 are in a straightenedconfiguration. Although this configuration the bellows are described as“straightened”, the term as used herein means that the bellows 720, 722,724 are straighter than the configuration described below with respectto FIG. 33, wherein filter 710 is radially expanded. Further, magnets712, 714, 716, 718 are described as spaced from each other in theradially compressed or delivery configuration of filter 710. As usedherein, the magnets 712, 714, 716, 718 are spaced a first distance fromeach other that is greater than the distance that they are spaced fromeach other when filter 710 is in the radially expanded or deployedconfiguration of FIG. 33. In FIG. 32, the radially force of sheath 708on filter 710 overcomes the magnetic attraction force between magnets712, 714, 716, 718 to keep magnets 712, 714, 716, 718 spaced relative toeach other and filter 710 in the radially compressed or deliveryconfiguration.

When embolic protection device 700 is advanced to a desired deploymentlocation within a vessel, sheath 708 is retracted, as shown in FIG. 33.With sheath 708 no longer applying radial pressure on filter 710, theattractive magnetic force between magnets 712, 714, 716, 718 causesintermediate magnet 714 to slide towards distal magnet 712, intermediatemagnet 716 to slide towards intermediate magnet 714, an proximal magnet718 to slide towards intermediate magnet 716, thereby expanding filter710, as shown in FIG. 33. Stopping magnets 714, 716, 718 so that theymove distally a desired amount can be accomplished in several ways. In anon-limiting embodiment, the attractive magnetic force between magnets712, 714, 716, 718 is designed to be less than the radial force of thevessel such that the vessel stops expansion of filter 710. In anothernon-limiting embodiment, as bellows 720, 722, 724 are longitudinallycompressed, each applies a force resisting the movement of intermediatemagnet 714 towards distal magnet 712, intermediate magnet 716 towardsintermediate magnet 714, and proximal magnet 718 towards intermediatemagnet 716, respectively. In another non-limiting embodiment, stops (notshown) may be provided on inner shaft 706 to prevent movement of magnets714, 716, 718 beyond a desired point. In another non-limiting example,other forces of filter assembly 702 prevent magnets 714, 716, 718 fromsliding past a desired location of inner shaft 706. Those skilled in theart would recognize other methods to assure the proper deployment sizeof filter 710.

After filter assembly 702 is deployed, sheath 708 may be removed (notshown) and a procedure upstream of filter 710 may be performed. Withfilter assembly 702 deployed as shown in FIG. 33, blood flow through thevessel passes through filter 710 and emboli are captured by filter 710.

When the procedure for which the embolic protection device 700 wasutilized is completed, filter assembly 702 is radially compressed into aretrieval configuration, shown in FIG. 34. Filter assembly 702 isradially compressed by injecting a fluid, such as saline, into annularlumen 728. Such a fluid is injected into annular lumen 728 at a proximalend of embolic protection device (not shown) through an inflation port(not shown). Such inflation ports at proximal ends of catheters are wellknown to those skilled in the art, for example, as used in ballooncatheters. As the fluid is injected into annular lumen 728, the fluidcontinues distally to lumens 721, 723, and 725 described above. When thelumens are filled and pressure continues to build, bellows 720, 722, 724expand longitudinally. This longitudinal expansion of bellows 720, 722,724 overcomes the magnetic attraction force between magnets 712, 714,716, 718 such that intermediate magnet 714 moves away from distal magnet712, intermediate magnet 716 moves away from intermediate magnet 714,and proximal magnet 718 moves away from intermediate magnet 716, asshown in FIG. 34. This movement causes proximal end 717 of filter 710 tomove away from distal end 711 of filter 710, thereby radiallycompressing filter 710, as shown in FIG. 34. Filter assembly 702 maythen be pulled into sheath 708 or a separate recapture sheath, or sheath708 or a separate recapture sheath may be pushed distally over filterassembly 702.

While FIGS. 32-34 show four magnets 712, 714, 716, 718 with threebellows 720, 722, 724 disposed therebetween, those skilled in the artwould recognize that more or less magnets and bellows may be used.

FIGS. 35-37 show schematically an embolic protection device 800 and amethod of deploying and retrieving embolic protection device 800. FIGS.35-37 do not show embolic protection device 800 deployed within a vesselfor clarity. However, it would be understood by those skilled in the artthat embolic protection device 800 can be deployed within a vessel, suchas vessel 420 shown schematically in FIGS. 23-25. Embolic protectiondevice 800 includes a filter assembly 802, a distal tip 804, an innershaft 806, and an outer shaft or sheath 808. Distal tip 804 may beintegral with inner shaft 806 or may be a distal end of a guidewireextending through a lumen of inner shaft 806. Filter assembly 802includes a filter 810 having a distal end 811 coupled to inner shaft 806at a distal connection 812 and a proximal end 813 to inner shaft 806 ata proximal connector 814. Distal connection 812 is coupled to innershaft 806 such that distal connection 812 does not slide relative toinner shaft 806. Proximal connection is slidably coupled to inner shaft806 such that proximal connection 814 can slide relative to inner shaft806. A shaft 824 is coupled to proximal connector 822 and is slidablerelative to inner shaft 806.

Filter assembly 802 further includes magnets 816, 818 disposed on afirst side of filter 810 and magnets 820, 822 disposed on an opposingside of filter 810. Magnets 816, 818, 820, 822 are oriented such thatthere is an repulsive magnetic force between magnets 816 and 820 and arepulsive magnetic force between magnets 818 and 822, as indicated bythe magnetic pole indications in FIG. 35.

Filter 810 as shown in FIGS. 35-37 is a single mesh filter. However,those skilled in the art would recognize that a dual mesh filter, suchas the filters described with respect to FIGS. 26-28 and 29-31 couldalso be used with the embolic protection device 800 of FIGS. 35-37.Filter 810 may be a mesh filter having pores in the range of 10-400microns. However, as known to those skilled in the art different sizesmay be utilized depending on the intended location of filter 810 and thetype of procedure for which filter 810 is being utilized. Filter 810 maybe any material suitable for use in a filter. For example, and not byway of limitation, stainless steel, nitinol, polymers, or otherfilaments may be used to form filter 810. As described in more detailbelow, filter 810 need not be a shape memory material due to the use ofmagnets 816, 818, 820, 822 to open filter 810.

Embolic protection device 800 is shown in FIG. 35 in a delivery orradially compressed configuration with sheath 808 extended over filter810 and proximal connection 814 is disposed relatively spaced apart fromdistal connection 812. A radially inward force from sheath 808 overcomesthe repulsive magnetic force between magnets 816, 820 and magnets 818,822 such that filter 810 remains in the delivery configuration shown inFIG. 35.

When embolic protection device 800 is advanced to a desired deploymentlocation within a vessel, sheath 808 is retracted, as shown in FIG. 36.With sheath 808 no longer applying radial force on filter 810, therepulsive magnetic force between magnets 816, 820 and 818, 822 (asindicated by arrows A) causes opposing sides of filter 810 to move awayfrom each other, as shown in FIG. 36. As opposing sides of filter 810move away from each other, proximal connection 814 slides towards distalconnection 812, as also shown in FIG. 36. These movements result in theradially expanded or deployed configuration shown in FIG. 36. Therepulsive magnetic force between magnets 816, 820 and magnets 818, 822ensures that filter 810 is firmly planted against the vessel wall sothat emboli do not escape around filter 810 when deployed as describedbelow. Ensuring that magnets 816, 820 and magnets 818, 820 separate bythe desired amount can be accomplished in several ways. In oneembodiment, the repulsive magnetic force between magnets 816, 820 andmagnets 818, 822 is designed to be less than the radial force of thevessel such that the vessel stops expansion of filter 810. In anotherembodiment, design features of filter assembly 802 and the amount of therepulsive magnetic force stop expansion of filter 810. In onenon-limiting example, the repulsive magnetic force between magnets 816,820 and magnets 818, 822 is such that when magnets 816, 818 reach acertain distance away from magnets 820, 822, respectively, the repulsiveforce is no longer large enough to cause the magnets to separate. Inanother non-limiting example, a stop (not shown) is provided on innershaft 806 to prevent proximal connector 814 from sliding past a desiredlocation. In another non-limiting example, forces from filter assembly802 prevent expansion of filter 810 beyond a desired amount. Thoseskilled in the art would recognize other methods to assure the properdeployment size of filter 810.

After filter assembly 802 is deployed, sheath 808 may be removed (notshown) and a procedure upstream of filter 810 may be performed. Withfilter assembly 802 deployed as shown in FIG. 36, blood flow through thevessel passes through filter 810, which captures emboli in thebloodstream.

When the procedure for which the embolic protection device 800 wasutilized is completed, filter assembly 802 is radially compressed into aretrieval configuration, shown in FIG. 37. Filter assembly 802 isradially compressed by pulling shaft 824, which is coupled to slidableproximal connector 814. This pulling force overcomes the repulsivemagnetic force between magnets 816, 820 and the repulsive magnetic forcebetween magnets 818, 822 such that proximal connection 814 movesproximally as indicated by arrow B, as shown in FIG. 37. Filter assembly802 may then be pulled into sheath 808 or a separate recapture sheath,or sheath 808 or a separate recapture sheath may be pushed distally overfilter assembly 802.

Although proximal and distal connections 814, 812 in FIGS. 35-37 havenot been described as magnets, those of ordinary skill in the art wouldrecognize that proximal and distal connections 814, 812 may be proximaland distal magnets such as those described with respect to FIGS. 23-25.Thus, in addition to the repulsive magnetic force between magnets 816,820 and the repulsive magnetic force between magnets 818, 822, anattractive magnetic force between proximal connection 814 and distalconnection 812 would slide proximal connection 814 towards distalconnection 812. Accordingly, with such a variation, a magnet could beused to convert filter 810 from the radially expanded or deployedconfiguration of FIG. 36 to the radially compressed configuration ofFIG. 37, as explained above with respect to FIG. 25.

While various embodiments according to the present invention have beendescribed above, it should be understood that they have been presentedby way of illustration and example only, and not limitation. It will beapparent to persons skilled in the relevant art that various changes inform and detail can be made therein without departing from the spiritand scope of the invention. It will also be understood that each featureof each embodiment discussed herein, and of each reference cited herein,can be used in combination with the features of any other embodiment.Further, while the embodiment described above have referred to magnets,the term as used herein refers to permanent magnets and magnetizedmaterials. All patents and publications discussed herein areincorporated by reference herein in their entirety.

What is claimed is:
 1. An embolic protection device comprising: a shafthaving a distal portion; a first magnet fixedly coupled to the distalportion of the shaft; a second magnet slidingly coupled to the shaftproximal to the first magnet; and a filter including a distal portioncoupled to the first magnet and a proximal portion coupled to the secondmagnet.
 2. The embolic protection device of claim 1, wherein the firstmagnet and the second magnet are magnetically attracted to each othersuch that the second magnet slides along the shaft toward the firstmagnet to radially expand the filter.
 3. The embolic protection deviceof claim 1, further comprising: at least a third magnet disposed betweenthe first magnet and the second magnet, wherein the at least thirdmagnet is slidingly coupled to the shaft; and bellows coupled betweenthe first magnet and the third magnet and between the third magnet andthe second magnet such that there is an annular lumen disposed betweenthe shaft and the bellows.
 4. The embolic protection device of claim 3,wherein the third magnet is magnetically attracted to the first magnetand the second magnet is magnetically attracted to the third magnet suchthat the second magnet slides toward the third magnet and the thirdmagnet slides toward the first magnet to radially expand the filter byreducing the longitudinal distance between the proximal and distalportions of the filter, and wherein a fluid injected into the annularlumen longitudinally expands the bellows to move the third magnet awayfrom the first magnet and the second magnet away from the third magnetto increase the longitudinal distance between the proximal and distalportions of the filter to radially compress the filter.
 5. An embolicprotection system comprising: an inner shaft; a filter having a firstfilter portion and a second filter portion, the first filter portionincluding a first filter proximal end and a first filter distal end, andthe second filter portion including a second filter proximal end and asecond filter distal end; a first magnet fixedly coupled to a distalportion of the inner shaft, the second filter distal end coupled to thefirst magnet; a second magnet slidingly coupled to the inner shaftproximal to the first magnet, the first filter proximal end coupled tothe second magnet, and the first filter distal end coupled to the secondfilter proximal end; a connector slidingly coupled to the inner shaftproximal of the second magnet; and a plurality of support arms, aproximal end of the support arms coupled to the connector and a distalend of the support arms coupled to the filter.
 6. The emboli protectionsystem of claim 5, wherein the first magnet and the second magnet areoriented such that the first magnet and the second magnet aremagnetically attracted to each other, and wherein in a radiallycompressed configuration the second magnet is spaced a first distancefrom the first magnet, and wherein in a radially expanded configurationthe second magnet is spaced a second distance from the first magnet,wherein the second distance is smaller than the first distance.
 7. Theemboli protection system of claim 6, wherein the radially compressedconfiguration a sheath provides a radial force preventing the secondmagnet from sliding towards the first magnet, and wherein the system isconfigured such that upon retraction of the sheath, the second magnetslides towards the first magnet due to the magnetic attraction betweenthe first magnet and the second magnet.
 8. The emboli protection systemof claim 5, wherein the first magnet and the second magnet are orientedsuch that the first magnet and the second magnet are magneticallyrepulsed from each other, and wherein in a radially compressedconfiguration the second magnet is spaced a first distance from thefirst magnet, and wherein in a radially expanded configuration thesecond magnet is spaced a second distance from the first magnet, whereinthe second distance is larger than the first distance.
 9. The emboliprotection system of claim 8, wherein the radially compressedconfiguration a sheath provides a radial force preventing the secondmagnet from sliding away from the first magnet, and wherein the systemis configuration such that upon retraction of the sheath, the secondmagnet slides away from the first magnet due to the magnetic repulsionbetween the first magnet and the second magnet.
 10. The emboliprotection device of claim 5, wherein the first filter portion has afirst pore size and the second filter portion has a second pore size,wherein the first pore size is larger than the second pore size.
 11. Anemboli protection device comprising: an inner shaft; a filter meshhaving a first end fixedly coupled to the inner shaft and a second endslidably coupled to the inner shaft; a first magnet attached to thefilter mesh to a first side of the inner shaft; and a second magnetattached to the filter mesh to a second side of the inner shaft oppositethe first side of the inner shaft, wherein the first magnet and thesecond magnet are oriented to magnetically repel each other such thefilter radially expands.
 12. The emboli protection device of claim 11,wherein the first magnet comprises a first plurality of magnets and thesecond magnet comprises a second plurality of magnets.
 13. An emboliprotection system comprising: a filter including a closed end and anopen end when the filter is in a radially expanded configuration; aplurality of first magnets coupled to the open end of the filter; and aretrieval catheter having a distal opening and a plurality of secondmagnets disposed around said opening such that the plurality of secondmagnets substantially align with the plurality of second magnets whenthe retrieval catheter is near the open end of the filter such that theplurality of first magnets are magnetically attracted to the pluralityof second magnets.
 14. The emboli protection system of claim 13, whereinthe catheter distal opening is substantially the same size as the openend of the filter.